Who is Disqualified for the Prize?

From Tim's sermon on 5/30/2010: "Self-Control"

1 Corinthians 9:23, 26-27: "I do all this for the sake of the gospel, that I might share in its blessings...Therefore, I do not run like a man running aimlessly; I do not fight like a man beating the air. No, I beat my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize."

Tim's Explanation:

Now, you think that’s what Paul’s saying? That [salvation is] the prize? That [salvation is] the crown that will last forever? No. Because if that’s what he was saying, that he’s working so hard to be a good Christian...he’s contradicting everything else he’s said anywhere else in the bible, because everywhere, Paul’s always saying: “I am saved in Christ, I am accepted, salvation is a gift, it’s not something I run for..."

Well, then, what is it? See, the goal that will give you self-control...is not just pleasing God, though of course you’re going to please God. It’s not that general, it’s not that abstract. It’s in verse 23. He says: "I do all this for the sake of the gospel, that I may share in its blessings."

...First of all, the word "share." There are two aspects of this very complex verb that can’t be gotten across with the simple English translation. First of all, the word share means: “Share with others something you already have.” So the first thing he’s saying is “The great passion of my life is not to get salvation, I’ve already got it, but to share the blessings that I’m having.” What Paul’s saying is: “I'm experiencing some kind of bliss, some kind of joy, some kind of beauty, something in the gospel, and I don’t want to enjoy it alone!”

...That’s not all he’s talking about...because this word that can be translated “share” can also be translated “participate,” and what he’s saying is: “I want to participate in the gospel in such a way that all kinds of other people experience the blessings I’m having in it.” What does that mean? And all the commentators are actually in agreement about it: Paul’s trying to say, not simply that he wants to evangelize people...what he’s actually saying is: "I want to so embody the gospel, I want to so participate in the gospel, I want to so reflect the gospel, I want to so display the gospel in my life, that anybody (anybody at all) who looks into my heart, into my life, will see how the gospel operates, will see the beauty that I see in it."

My Question: If Tim is right about the definition of "prize", then who could possibly be "disqualified"? I think Tim is saying that the "prize" is not salvation, but a greater measure of participation/sharing in the gospel. So the hypothetical person who's disqualified has received salvation, but participates/shares in the gospel less than what is theoretically possible, or less than God desires?

I'm sure Paul sought (for himself and others) more than mere conversion, but I'm not sure how this richer scheme fits with the image/metaphor of "disqualification".